In 1977 Weiss and Grimes, by means of mass spectrometry and 1H and 11B NMR spectroscopy, proposed two structures (I and II) for the ferraborane (η5‐C5H5)Fe(B5H10), isoelectronic with ferrocene. In this work, by means of high‐level quantum‐chemical computations, we confirm the experimental structures of the two isomers with their corresponding energies, and assign the reported 1H and 11B NMR chemical shifts. A striking result from this study is the planarization (3D → 2D) of the B5H10– ligand ‐ an unknown isolated anion, isoelectronic with aromatic cyclopentadienyl anion C5H5– ‐ when attached to the (η5‐C5H5)Fe+ moiety, thus resulting in a more stable ferraborane isomer II.

中文翻译：

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热重排中显着的硼烷平坦化 (η5-C5H5)Fe(η3-B5H10) → (η5-C5H5)Fe(η5-B5H10) §

1977年，Weiss和Grimes通过质谱、1H和11B核磁共振波谱，提出了与二茂铁等电子的铁硼烷(η5-C5H5)Fe(B5H10)的两种结构（I和II）。在这项工作中，通过高级量子化学计算，我们确认了两种异构体的实验结构及其相应的能量，并指定了报道的 1H 和 11B NMR 化学位移。这项研究的一个惊人结果是 B5H10– 配体（一种未知的孤立阴离子，与芳香族环戊二烯基阴离子 C5H5– 等电子）连接到 (η5-C5H5)Fe+ 部分时平面化（3D → 2D），从而产生更多稳定的铁硼烷异构体II。